Re: [PATCH] exec: refactor an invalid executable check to use isprint

[Al Viro]

On Fri, Nov 15, 2024 at 04:53:51PM +0000, Nir Lichtman wrote:
> Remove private printable macro that is defined in exec.c and migrate to
> using the public isprint macro instead


> -#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))

> -		if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
> -		    printable(bprm->buf[2]) && printable(bprm->buf[3]))
> +		if (isprint(bprm->buf[0]) && isprint(bprm->buf[1]) &&
> +		    isprint(bprm->buf[2]) && isprint(bprm->buf[3]))

RTFM(isprint).  Or run a trivial loop and check what it does, for that
matter.

isprint('\t') is false.  So's isprint('\n').